1. Field of the Invention
The present invention relates to a toner pack for use with the developing device in the electrophotographic apparatus. It also relates to a method of filling up toner in the toner pack into the developing device.
2. Description of the Related Art
The electrophotographic apparatus is used in the copying machine, facsimile, laser printer and others. The electrophotographic apparatus houses a photosensitive drum, around which charging, exposing, developing, transferring and fixing devices are arranged in this order in the rotating direction of the drum.
The photosensitive drum is rotated by a drive means. The surface of the drum thus rotated is charged by the charging device. The surface of the drum is then exposed by the exposing device to form a latent image thereon. Further, toner is supplied from the developing device onto the surface of the drum to form a toner image thereon. The toner image on the surface of the drum is then transferred onto a sheet of the recording paper by the transferring device. Further, the toner image on the recording paper is fixed by the fixing device.
The developing device in the electrophotographic apparatus includes a body in which toner is stored, and toner in the device body is supplied onto the surface of the photosensitive drum. When toner in the device body is reduced to a low amount in the device body, it is newly filled up in the device body.
The toner pack exchanging system is used to fill up toner in the body of the developing device. A toner pack in which toner is stored is detachably set at the body of the developing device. When the device body becomes empty, the toner pack is detached from the device body and a new toner pack is set in it.
According to this system, toner is filled up from the toner pack directly into the device body. When toner is to be filled up, therefore, it can be prevented from scattering outside the device body to soil the device and its surroundings.
The conventional toner pack used by the toner pack exchanging system includes a toner box and a seal sheet. The toner box is shaped like a rectangle and provided with an opening at the bottom thereof and a toner inlet independent of the opening.
The seal sheet is peelably bonded to the rim of the opening of the toner box by heat to thereby seal the opening. The toner box is filled with toner through the toner inlet thereof. The toner inlet of the toner box is closed by a cap. The seal sheet has a length longer than two times the length of the opening of the toner box. That portion of the seal sheet which is not bonded to the opening is turned outside along the opening of the toner box.
The body of the developing device has an opening at the top thereof. The toner box is detachably attached to the opening of the device body. The free end of the seal sheet is projected outside from between the toner box and the device body when the toner box is set at the device body as described above. The free end of the seal sheet is pulled by the operator. The seal sheet is thus pulled outside the device body and gradually peeled off the opening of the toner box. The opening of the toner box is thus gradually opened. When the whole of the opening of the toner box is opened, toner in the toner box is dropped into the device body through the opening of the toner box and then through the opening of the device body. After toner is filled up in the device body, the toner box is used as a cover for the opening of the device body. When the amount of toner becomes small and it must be filled up in the device body, the toner box is detached from the device body and a new toner box is set at the opening of the device body.
However, the conventional toner pack has the following problems.
The inner face of that portion of the seal sheet which is bonded to the opening of the toner box is opposed to the inside of the toner box. Toner in the toner box, therefore, adheres to this inner face of the seal sheet. When that portion of the seal sheet which is bonded to the opening of the toner box is peeled off, therefore, it is pulled outside from between the toner box and the device body with its toner-adhering face directed downward.
Toner adhering to the inner face of the seal sheet is thus scattered to soil the inside of the electrophotographic apparatus.
Further, when the peeled-off seal sheet is handled by the operator, toner adhering to the seal sheet is also scattered to soil the surroundings of the apparatus and the clothes of the operator.